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Building Decarbonisation

Area: Design, planning and building

Decarbonisation, a term which echoes through the corridors of academia, politics, practical applications, and stands at the forefront of contemporary discussions on sustainability. Intricately intertwined with concepts such as net-zero and climate neutrality, it represents a pivotal shift in our approach to environmental sustainability. In its essence, decarbonisation signifies the systematic reduction of carbon dioxide intensity, a crucial endeavour in the battle against climate change (Zachmann et al., 2021).

This overview delves into the multifaceted concept of decarbonisation within the context of the European Union. Beginning with a broad perspective, we examine its implications at the macro level before homing in on the complexities of decarbonisation within the realm of building structures. Finally, we explore the literature insights, presenting key strategies that pave the way toward achieving a decarbonised building sector.

From a broad perspective, decarbonisation is an overarching concept that aims to achieve climate neutrality (Zachmann et al., 2021, p.13). Climate neutrality means achieving a state of equilibrium between greenhouse gas emissions and their removal from the atmosphere, preventing any net increase in atmospheric CO2 concentration (IEA, 2022). From an energy decarbonisation perspective, however, in a document provided by the Economic, Scientific and Quality of Life Policy Department at the request of the Industry, Research and Energy (ITRE) Committee, Zachmann et al. (2021) explain that energy systems require a fundamental shift in the way societies provide, transport and consume energy (Zachmann et al., 2021). In the construct of decarbonisation, as outlined by the Intergovernmental Panel on Climate Change (IPCC), the focus lies on strategic directives aimed at reducing the carbon content of energy sources, fuels, products and services (Arvizu et al., 2011; Edenhofer et al., 2011). This complex process involves the transition from carbon-intensive behaviours, such as fossil fuel use, to low-carbon or carbon-neutral alternatives. The main goal of decarbonisation, therefore, is to reduce emissions of greenhouse gases such as CO2 and methane, which are closely linked to the growing threats of climate change (Edenhofer et al., 2011).

Hoeller et al. (2023) explain that decarbonisation efforts within the Organisation for Economic Co-operation and Development (OECD) focus on harmonising economic growth, energy production and consumption with climate objectives to mitigate the adverse effects of climate change while promoting sustainable development (Hoeller et al., 2023). From a pragmatic perspective, however, according to the OECD Policy Paper 31: A framework to decarbonise the economy, published in 2022,  progress on economic decarbonisation remains suboptimal. This raises the urgent need for a multi-dimensional framework that is not only cost-effective but also inclusive and comprehensive in its strategy for decarbonisation (D’Arcangelo et al., 2022). D’Arcangelo et al. (2023) add that such framework should include several steps such as setting clear climate targets, measuring progress and identifying areas for action, delineating policy frameworks, mapping existing policies, creating enabling conditions, facilitating a smooth transition for individuals, and actively engaging the public.

From an academic perspective, Weller and Tierney (2018) provide an explanation of decarbonisation, defining it as a twofold concept. Firstly, it involves reducing the intensity of fossil fuel use for energy production. Secondly, it emphasises the role of policy in mitigating the negative externalities associated with such use. They argue that decarbonisation is a politically charged policy area that needs to be 'just', while also serving a means to revitalise local economies (Weller & Tierney, 2018). Kyriacou and Burke (2020) expand on this definition, highlighting decarbonisation as the transition from a high-carbon to a low-carbon energy system. This transition is driven by the need to mitigate climate change without compromising energy security. Boute (2021), on the other hand, emphasises the long-term structural reduction of CO2 emissions as the core strategy of decarbonisation. Boute adds that the effectiveness of decarbonisation must be measured in terms of a unit of energy consumed across all activities. In the economic context, the Oxford Institute for Energy Studies concludes that decarbonisation aims to reduce the carbon intensity of an economy. This reduction is quantified as the ratio of CO2 emissions to gross domestic product (Henderson & Sen, 2021). Addressing methodological concerns, Buettner (2022) added that decarbonisation is often misused as a generic term. Moreover, Buettner highlights the diverse levels at which decarbonisation occurs, ranging from carbon neutrality (focused on reducing CO2 emissions), to climate neutrality (aiming to reduce CO2, non-fluorinated greenhouse gases, and fluorinated greenhouse gases) and, finally, to environmental neutrality (which reduces all substances negatively impacting the environment and health) (Buettner, 2022).

The debate on the decarbonisation of the construction sector revolves around similar issues. The report on Decarbonising Buildings in Cities and Regions, published by the OECD in 2022, defines the concept as reducing energy consumption by improving envelope insulation, installing high performance equipment, and scaling up the use of renewable sources to meet the energy demands (OECD, P24). Another definition comes from a working paper by the OECD Economics Department, Hoeller et al. (2023) contend, it is necessary to consider direct emissions from household fossil fuel combustion and indirect emissions from the generation of electricity and district heating used by households (Hoeller et al., 2023). The comprehensive study “Decarbonising Buildings” published by the Climate Action Tracker (CAT) in 2022, defines the term as transforming the building sector to achieve net zero emissions by 2050. Achieving this goal requires various technological solutions and behavioural changes to decarbonise heating and cooling, such as energy-efficient building envelopes, heat pumps and on-site renewables (CAT, 2022). Gratiot et al. (2023) consider decarbonisation as the process of reducing or eliminating CO2 emissions that contribute to climate change from a building’s energy sources. This involves systematically shifting buildings from carbon-intensive energy sources (e.g., gas, oil and coal) to low-carbon or carbon-neutral alternatives (e.g., solar, wind and geothermal). This process includes improving the energy efficiency of buildings through better insulation, lighting and appliances (Gratiot et al., 2023). Blanco et al. (2021) consider the decarbonisation of buildings and operation of buildings. This includes enhancing the energy efficiency of buildings and minimizing embodied carbon from building materials and construction activities of greenhouse gas emissions from the construction and operation of buildings.

Achieving a decarbonised building sector is a multifaceted endeavour that demands extensive efforts in several key areas, such as energy sources, building envelope, building policy and transformation funds. The objective of the energy transition is to shift from reliance on fossil fuels to clean or renewable energy sources, primarily used for heating and cooling, such as heat pumps, district heating, hydrogen (Jones, 2021). Decarbonising the building envelope, on the other hand, involves improving the energy efficiency of buildings through better insulation, lighting and appliances. It also necessitates minimising embodied carbon from building materials and construction activities (CAT, 2022; D’Arcangelo et al., 2022). Incorporating effective policies into building construction is crucial. This includes adopting of performance standards and building codes that regulate the energy use and emissions of both new and existing buildings. These regulations directly impact the extent and pace of decarbonisation (CAT, 2022; Jones, 2021). Additionally, it is essential to establish a clear vision and climate targets for the buildings sector and operationalise them with a comprehensive policy mix that encompass emissions pricing, standards, regulations and complementary measures (Jones, 2021). The most significant challenge lies in financing the transition to a decarbonised sector. Therefore, it is imperative to mobilise finance on a large scale and collaborate with industry stakeholders. This collaboration is vital to facilitate the transition, overcome barriers, and manage the costs associated with deploying low- or zero-carbon technologies (D’Arcangelo et al., 2022).

In summary, the overarching concept of decarbonisation primarily targets the reduction of carbon dioxide in economic and industrial activities, with a focus on energy production and distribution systems. At the building level, the emphasis lies in integrating low-carbon or carbon-neutral systems to minimise both direct and indirect emissions. Nevertheless, the literature examined indicates that other societal aspects, including social and behavioural factors, have not been thoroughly researched. This gap in knowledge could challenge the realisation of the goal of carbon neutrality by 2050 and underscores the need for further studies in these areas.

References

Arvizu, D., Bruckner, T., Christensen, J., Chum, H., Devernay, J. M., Faaij, A., Fischedick, M., Goldstein, B., Hansen, G., Huckerby, J., Jäger‐Waldau, A., Kadner, S., Kammen, D., Krey, V., Kumar, A., Lewis, A., Lucon, O., Matschoss, P., Maurice, L., Mitchell, C., Moomaw, W., Moreira, J., Nadai, A., J. Nilsson, L., Nyboer, J., Rahman, A., Sathaye, J., Sawin, J., Schaeffer, R., Schei, T., Schlöm, S., Sims, R., von Stechow, C., Verbruggen, A., Urama, K., Wiser, R., Yamba, F., & Zwickel, T. (2011). Summary for Policymakers, IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation (O. Edenhofer, R. Pichs‐Madruga, Y. Sokona, & K. Seyboth, Eds. Vol. 20). Cambridge University Press.

Blanco, J., Engel, H., Imhorst, F., Ribeirinho, M., & Sjodin, E. (2021). Call for action: Seizing the decarbonization opportunity in construction. C&Mckinsey (ed.). Retrieved August from (https://www.mckinsey.com/industries/engineering-construction-and-building-materials/our-insights/call-for-action-seizing-the-decarbonization-opportunity-in-construction#/).

Boute, A. (2021). Environmental Force Majeure: Relief from Fossil Energy Contracts in the Decarbonisation Era. Journal of Environmental Law, 33(2), 339-364.

Buettner, S. M. (2022). Roadmap to neutrality—What foundational questions need answering to determine one’s ideal decarbonisation strategy. Energies, 15(9), 3126.

CAT. (2022). Decarbonising Buildings Achieving zero carbon heating and cooling. Climate Action Tracker. Retrieved from (https://climateactiontracker.org/publications/decarbonising-buildings-achieving-net-zero-carbon-heating-and-cooling)

D’Arcangelo, F. M., Levin, I., Pagani, A., Pisu, M., & Johansson, Å. (2022). Economic Policy Paper No. 31: A framework to decarbonise the economy. OECD Publishing. Retrieved from (https://www.oecd-ilibrary.org/deliver/4e4d973d-en.pdf?itemId=/content/paper/4e4d973d-en&mimeType=pdf).

Edenhofer, O., Pichs-Madruga, R., Sokona, Y., Seyboth, K., Kadner, S., Zwickel, T., Eickemeier, P., Hansen, G., Schlömer, S., & von Stechow, C. (2011). Renewable energy sources and climate change mitigation: Special report of the intergovernmental panel on climate change. Cambridge University Press.

Gratiot, N., Klein, J., Challet, M., Dangles, O., Janicot, S., Candelas, M., Sarret, G., Panthou, G., Hingray, B., & Champollion, N. (2023). A transition support system to build decarbonization scenarios in the academic community. PLOS Sustainability and Transformation, 2(4): e0000049. https://doi.org/10.1371/journal.pstr.0000049.

Henderson, J., & Sen, A. (2021). The Energy Transition: Key challenges for incumbent and new players in the global energy system. OIES Paper: ET.

Hoeller, P., Ziemann, V., Cournède, B., & Bétin, M. (2023). Working Papers No. 1751-Home, green home: Policies to decarbonise housing. OECD Publishing. Retrieved from (https://www.oecd-ilibrary.org/deliver/cbda8bad-en.pdf?itemId=/content/paper/cbda8bad-en&mimeType=pdf).

IEA. (2022). Advancing Decarbonisation through Clean Electricity Procurement. International Energy Agency. Retrieved from (https://www.iea.org/reports/advancing-decarbonisation-through-clean-electricity-procurement)

Jones, E. (2021). The need for decarbonisation. Journal of Building Services Engineering Research and Technology 42(3), 42(3), 253-255.

Kyriacou, G., & Burke, J. (2020). What is 'decarbonisation' of the power sector? Why do we need to decarbonise the power sector in the UK?. The London School of Economic and Political Science & Grantham Research Institute. Retrieved from (https://www.lse.ac.uk/granthaminstitute/explainers/what-is-decarbonisation-of-the-power-sector-why-do-we-need-to-decarbonise-the-power-sector-in-the-uk/)

Weller, S., & Tierney, J. (2018). Evidence in the networked governance of regional decarbonisation: A critical appraisal. Australian Journal of Public Administration, 77(2), 280-293.

Zachmann, G., Holz, F., McWilliams, B., Meissner, F., Roth, A., Sogalla, R., & Kemfert, C. (2021). Decarbonisation of Energy: Determining a robust mix of energy carriers for a carbon-neutral EU. European Parliament, Policy Department for Economic, Scientific and Quality of Life Policies. Retrieved from (https://www.europarl.europa.eu/RegData/etudes/STUD/2021/695469/IPOL_STU(2021)695469_EN.pdf)

 

 

Created on 06-11-2023 | Update on 23-10-2024

Related definitions

Sustainability

Author: E.Roussou (ESR9)

Area: Community participation

Sustainability is primarily defined as 'the idea that goods and services should be produced in ways that do not use resources that cannot be replaced and that do not damage the environment' (Cambridge Advanced Learner’s Dictionary & Thesaurus, n.d.) and is often used interchangeably with the term “sustainable development”(Aras & Crowther, 2009). As defined by the UN, sustainable development is the effort to “meet the needs of the present without compromising the ability of future generations to meet their own needs” (United Nations, 1987) and is often interpreted as the strategies adopted towards sustainability with the latter being the overall goal/vision (Diesendorf, 2000). Both of these relatively general and often ambiguous terms have been a focal point for the past 20 years for researchers, policy makers, corporations as well as local communities, and activist groups, among others, (Purvis et al., 2019). The ambiguity and vagueness that characterise both of these terms have contributed to their leap into the global mainstream as well as the broad political consensus regarding their value and significance (Mebratu, 1998; Purvis et al., 2019), rendering them one of the dominant discourses in environmental, socio-political and economic issues (Tulloch, 2013). It is, however, highly contested whether their institutionalisation is a positive development. Tulloch, and Tulloch & Nielson (2013; 2014) argue that these terms -as they are currently understood- are the outcome of the “[colonisation of] environmentalist thought and action” which, during the 1960s and 1970s, argued that economic growth and ecological sustainability within the capitalist system were contradictory pursuits. This “colonisation” resulted in the disempowerment of such discourses and their subsequent “[subordination] to neoliberal hegemony” (Tulloch & Neilson, 2014, p. 26). Thus, sustainability and sustainable development, when articulated within neoliberalism, not only reinforce such disempowerment, through practices such as greenwashing, but also fail to address the intrinsic issues of a system that operates on, safeguards, and prioritises economic profit over social and ecological well-being (Jakobsen, 2022). Murray Bookchin (1982), in “The Ecology of Freedom” contends that social and environmental issues are profoundly entangled, and their origin can be traced to the notions of hierarchy and domination. Bookchin perceives the exploitative relationship with nature as a direct outcome of the development of hierarchies within early human societies and their proliferation ever since. In order to re-radicalise sustainability, we need to undertake the utopian task of revisiting our intra-relating, breaking down these hierarchical relations, and re-stitching our social fabric. The intra-relating between and within the molecules of a society (i.e. the different communities it consists of) determines how sustainability is understood and practised (or performed), both within these communities and within the society they form. In other words, a reconfigured, non-hierarchical, non-dominating intra-relationship is the element that can allow for an equitable, long-term setting for human activity in symbiosis with nature (Dempsey et al., 2011, p. 290). By encouraging, striving for, and providing the necessary space for all voices to be heard, for friction and empathy to occur, the aforementioned long-term setting for human activity based on a non-hierarchical, non-dominating intra-relating is strengthened, which augments the need for various forms of community participation in decision-making, from consulting to controlling. From the standpoint of spatial design and architecture, community participation is already acknowledged as being of inherent value in empowering communities (Jenkins & Forsyth, 2009), while inclusion in all facets of creation, and community control in management and maintenance can improve well-being and social reproduction (Newton & Rocco, 2022; Turner, 1982). However, much like sustainability, community participation has been co-opted by the neoliberal hegemony; often used as a “front” for legitimising political agendas or as panacea to all design problems, community participation has been heavily losing its significance as a force of social change (Smith & Iversen, 2018), thus becoming a depoliticised, romanticised prop. Marcus Miessen (2011) has developed a critical standpoint towards what is being labelled as participation; instead of a systematic effort to find common ground and/or reach consensus, participation through a cross-benching approach could be a way to create enclaves of disruption, i.e. processes where hierarchy and power relations are questioned, design becomes post-consensual spatial agency and participation turns into a fertile ground for internal struggle and contestation. Through this cross-benching premise, community participation is transformed into a re-politicised spatial force. In this context, design serves as a tool of expressing new imaginaries that stand against the reproduction of the neoliberal spatial discourse. Thus, sustainability through community participation could be defined as the politicised effort to question, deconstruct and dismantle the concept of dominance by reconfiguring the process of intra-relating between humans and non-humans alike.

Created on 08-06-2022 | Update on 23-10-2024

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Sustainability Built Environment

Author: M.Alsaeed (ESR5), K.Hadjri (Supervisor)

Area: Design, planning and building

Sustainability of the built environment The emergence of the contemporary environmental movement between the 1960s and 1970s and its proposals to remedy the consequences of pollution can be seen as one of the first steps in addressing environmental problems (Scoones, 2007). However, the term “sustainable” only gained wider currency when it was introduced into political discourse by the Club of Rome with its 1972 report “The Limits to Growth”, in which the proposal to change growth trends to be sustainable in the far future was put forward (Grober, 2007; Kopnina & Shoreman-Ouimet, 2015a; Meadows et al., 1972). Since then, the use of the term has grown rapidly, especially after the publication of the 1978 report “Our Common Future”, which became a cornerstone of debates on sustainability and sustainable development (Brundtland et al., 1987; Kopnina & Shoreman-Ouimet, 2015a). Although the two terms are often used indistinctively, the former refers to managing resources without depleting them for future generations, while the latter aims to improve long-term economic well-being and quality of life without compromising the ability of future generations to meet their needs (Kopnina & Shoreman-Ouimet, 2015b; UNESCO, 2015). The Brundtland Report paved the way for the 1992 Earth Summit, which concluded that an effective balance must be found between consumption and conservation of natural resources (Scoones, 2007). In 2000, the United Nations General Assembly published the 8 Millennium Development Goals (UN, 2000), which led to the 17 Sustainable Development Goals (SDGs) published in 2016 (UN, 2016). The 17 SDGs call on all countries to mobilise their efforts to end all forms of poverty, tackle inequalities and combat climate change (UN, 2020; UNDP, 2018). Despite the rapidly growing literature on sustainability, the term remains ambiguous and lacks a clear conceptual foundation (Grober, 2007; Purvis et al., 2019). Murphy (2012) suggests that when defining sustainability, the question should be: Sustainability, of what? However, one of the most prominent interpretations of sustainability is the three pillars concept, which describes the interaction between the social, economic and environmental components of society (Purvis et al., 2019). The environmental pillar aims to improve human well-being by protecting natural capital -e.g. land, air and water- (Morelli, 2011). The economic sustainability pillar focuses on maintaining stable economic growth without damaging natural resources (Dunphy et al., 2000). Social sustainability, on the other hand, aims to preserve social capital and create a practical social framework that provides a comprehensive view of people's needs, communities and culture (Diesendorf, 2000). This latter pillar paved the way for the creation of a fourth pillar that includes human and culture as a focal point in sustainability objectives (RMIT, 2017). Jabareen (2006) describes environmental sustainability as a dynamic, inclusive and multidisciplinary concept that overlaps with other concepts such as resilience, durability and renewability. Morelli (2011) adds that it can be applied at different levels and includes tangible and intangible issues. Portney (2015) takes Morelli's explanation further and advocates that environmental sustainability should also promote industrial efficiency without compromising society's ability to develop (Morelli, 2011; Portney, 2015). Measuring the built environment sustainability level is a complex process that deploys quantitative methods, including (1) indexes (e.g. energy efficiency rate), (2) indicators (e.g. carbon emissions and carbon footprint), (3) benchmarks (e.g. water consumption per capita) and (4) audits (e.g. building management system efficiency) (Arjen, 2015; Berardi, 2012; James, 2014; Kubba, 2012). In recent years, several rating or certification systems and practical guides have been created and developed to measure sustainability, most notably the Building Research Establishment Environmental Assessment Method (BREEAM) introduced in the UK in 1990 (BRE, 2016) and the Leadership in Energy and Environmental Design (LEED) established in the US in 2000 (USGBC, 2018). In addition, other overlapping methodologies and certification frameworks have emerged, such as the European Performance of Buildings Directive (EPBD) in 2002 (EPB, 2003) and the European Framework for Sustainable Buildings, also known as Level(s) in 2020 (EU, 2020), amongst others. The sustainability of the built environment aims to reduce human consumption of natural resources and the production of waste while improving the health and comfort of inhabitants and thus the performance of the built environment elements such as buildings and spaces, and the infrastructure that supports human activities (Berardi, 2012; McLennan, 2004). This aim requires an effective theoretical and practical framework that encompasses at least six domains, including land, water, energy, indoor and outdoor environments, and economic and cultural preservation (Ferwati et al., 2019). More recently, other domains have been added, such as health and comfort, resource use, environmental performance, and cost-benefit and risk (EU, 2020). Sustainability of the built environment also requires comprehensive coordination between the architectural, structural, mechanical, electrical and environmental systems of buildings in the design, construction and operation phases to improve performance and avoid unnecessary resource consumption (Yates & Castro-Lacouture, 2018).

Created on 24-06-2022 | Update on 16-11-2022

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Performance Gap in Retrofit

Author: S.Furman (ESR2)

Area: Design, planning and building

The performance gap in retrofit refers to the disparity between the predicted and actual energy consumption after a retrofit project, measured in kWh/m2/year. This discrepancy can be substantial, occasionally reaching up to five times the projected energy usage (Traynor, 2019). Sunikka-Blank & Galvin (2012) identify four key factors as contributing to the performance gap: (1) the rebound effect, (2) the prebound effect, (3) interactions of occupants with building components, and (4) the uncertainty of building performance simulation outcomes. Gupta & Gregg (2015) additionally identify elevated building air-permeability rates as a factor leading to imbalanced and insufficient extract flowrates, exacerbating the performance gap. While post occupancy evaluation of EnerPhit—the Passivhaus Institut certification for retrofit—has shown far better building performance in line with predictions, the human impact of building users operating the building inefficiently will always lead to some sort of performance gap (Traynor, 2019, p. 34). Deeper understanding of the prebound effect and the rebound effect can improve energy predictions and aid in policy-making (Galvin & Sunikka-Blank, 2016). Therefore, the ‘prebound effect’ and the ‘rebound effect’, outlined below, are the most widely researched contributors to the energy performance gaps in deep energy retrofit.   Prebound Effect The prebound effect manifests when the actual energy consumption of a dwelling falls below the levels predicted from energy rating certifications such as energy performance certificates (EPC) or energy performance ratings (EPR). According to Beagon et al. (2018, p.244), the prebound effect typically stems from “occupant self-rationing of energy and increases in homes of inferior energy ratings—the type of homes more likely to be rented.” Studies show that the prebound effect can result in significantly lower energy savings post-retrofit than predicted and designed to achieve (Beagon et al., 2018; Gupta & Gregg, 2015; Sunikka-Blank & Galvin, 2012). Sunikka-Blank & Galvin’s (2012) study compared the calculated space and water heating energy consumption (EPR) with the actual measured consumption of 3,400 German dwellings and corroborated similar findings of the prebound effect in the Netherlands, Belgium, France, and the UK. Noteworthy observations from this research include: (1) substantial variation in space heating energy consumption among dwellings with identical EPR values; (2) measured consumption averaging around 30% lower than EPR predictions; (3) a growing disparity between actual and predicted performance as EPR values rise, reaching approximately 17% for dwellings with an EPR of 150 kWh/m²a to about 60% for those with an EPR of 500 kWh/m²a (Sunikka-Blank & Galvin, 2012); and (4) a reverse trend occurring for dwellings with an EPR below 100 kWh/m²a, where occupants consume more energy than initially calculated in the EPR, referred to as the rebound effect. Galvin & Sunikka-Blank (2016) identify that a combination of high prebound effect and low income is a clear indicator of fuel poverty, and suggest this metric be utilised to target retrofit policy initiatives.   Rebound Effect The rebound effect materializes when energy-efficient buildings consume more energy than predicted. Occupants perceive less guilt associated with their energy consumption and use electrical equipment and heating systems more liberally post-retrofit, thereby diminishing the anticipated energy savings (Zoonnekindt, 2019). Santangelo & Tondelli (2017) affirm that the rebound effect arises from occupants’ reduced vigilance towards energy-related behaviours, under the presumption that enhanced energy efficiency in buildings automatically decreases consumption, regardless of usage levels and individual behaviours. Galvin (2014) further speculates several factors contributing to the rebound effect, including post-retrofit shifts in user behaviour, difficulties in operating heating controls, inadequacies in retrofit technology, or flawed mathematical models for estimating pre- and post-retrofit theoretical consumption demand. The DREEAM project, funded by the European Union, discovered instances of electrical system misuse in retrofitted homes upon evaluation (Zoonnekindt, 2019). A comprehensive comprehension of the underlying causes of the rebound effect is imperative for effective communication with all retrofit stakeholders and for addressing these issues during the early design stages.   Engaging residents in the retrofit process from the outset can serve as a powerful strategy to mitigate performance gaps. Design-thinking (Boess, 2022), design-driven approaches (Lucchi & Delera, 2020), and user-centred design (Awwal et al., 2022; van Hoof & Boerenfijn, 2018) foster socially inclusive retrofit that considers Equality, Diversity, and Inclusion (EDI). These inclusive approaches can increase usability of technical systems, empower residents to engage with retrofit and interact with energy-saving technology, and enhance residents’ energy use, cultivating sustainable energy practices as habitual behaviours. Consequently, this concerted effort not only narrows the performance gap but simultaneously enhances overall wellbeing and fortifies social sustainability within forging communities.

Created on 08-09-2023 | Update on 23-10-2024

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Thermal Insulation & Airtightness

Author: S.Furman (ESR2)

Area: Design, planning and building

Increasing the thermal properties of the building envelope is a passive strategy to reduce energy loss and ensure significant reductions in energy demand (Grecchi, 2022). Van den Brom et al (2019) define thermal renovation as “renovation measures that are taken to reduce energy consumption used for thermal comfort”, and group thermal insulation, airtightness and efficient electrical system into a single category. Accordingly, deep ‘thermal’ renovation occurs when significant improvement in at least three building components bring thermal performance to a level equal to or higher than the current building regulation standards (van den Brom et al., 2019). These building components include roof insulation, floor insulation, façade insulation, window improvements, heating system, domestic hot water system, and ventilation system (van den Brom et al., 2019). Other authors (Institute for Sustainability & UCL Energy Institute, 2012; Sojkova et al., 2019; Traynor, 2019) divide electrical systems into a further category for clearer practical application. The concept of airtightness is revered for saving energy, avoiding structural damage, contributing to thermal comfort (Bastian et al., 2022), and is key to reducing heat loss through ventilation (Roberts, 2008). Draught proofing involves draught-stripping, replacing leaky windows and closing off unused chimneys (Roberts, 2008). The location of an airtight layer should be identified, and all penetrations through it minimised, sealed, and recorded (Traynor, 2019). This airtight layer can be airtight board, a plastered wall, or a membrane with appropriate tape at all junctions such as window openings (Traynor, 2019). Triple-glazed windows in combination with any frame material are the most efficient glazing system at reducing primary energy cost and CO₂ emissions (Sojkova et al., 2019). All air pockets should be sealed to prevent draughts and thermal bridging. Thermal bridging should be eliminated wherever possible, although a comprehensive thermal reduction with low internal surface temperatures can prevent physical problems such as moisture and mould (Bastian et al., 2022). There are many forms of insulation to consider during retrofit that considerably contribute to a reduction in heat loss. Filling external cavity walls with insulation can reduce heat loss through walls by up to 40% (Roberts, 2008). Ground floor insulation and roof insulation are also necessary steps in DER (Grecchi, 2022; Roberts, 2008; Traynor, 2019). Ground floor insulation can occur in suspended timber floors between joists or above solid concrete floors (Traynor, 2019). Roof insulation can be added between structural elements, or using a ‘cold’ roof solution, with insulation laid or sprayed over the existing ceiling (Traynor, 2019). Alternatively, green roofs can reduce the amount of heat penetration through roofs, playing a similar role to roof insulation. This is done by absorbing heat into their thermal mass alongside the evaporation of moisture but will require structural upgrades to manage the new load (Roberts, 2008). External wall insulation (EWI) protects the building fabric, improves airtightness and is relatively quick and easy to install (Roberts, 2008). EWI can also help mitigate overheating by absorbing less heat than the original material, while allowing existing thermal mass from solid masonry walls and concrete to be retained within the insulated envelope (Bastian et al., 2022). The two main external insulation systems are ventilated rainscreen systems and rendered insulation systems (Roberts, 2008). EWI is inappropriate for historical building use because it will cover the historical architectural character. Gupta & Gregg’s (2015) preserved the original exterior façade by using internal wall insulation inside the front façade and EWI on all other façades. However, drawbacks to this solution can include the loss of internal floor area, and reduced energy efficiency as notable heat loss can occur where the internal insulated wall meets the external insulated wall (Gupta & Gregg, 2015).

Created on 25-10-2024 | Update on 08-11-2024

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